Which are the symptoms of Legionnaires' Disease?

Symptoms of Legionnaires' Disease

Legionnaires' disease is a severe form of pneumonia caused by the bacterium Legionella pneumophila. It is named after an outbreak that occurred in 1976 during an American Legion convention in Philadelphia. The disease primarily affects the lungs and can be life-threatening, especially for individuals with weakened immune systems or underlying health conditions.

Initial symptoms:

The symptoms of Legionnaires' disease usually appear within 2 to 10 days after exposure to the Legionella bacteria. The initial signs may resemble those of a severe flu or pneumonia, making it challenging to diagnose without specific testing. The early symptoms include:

• High Fever: A persistent high fever, often reaching 104°F (40°C), is one of the hallmark symptoms of Legionnaires' disease. The fever may be accompanied by chills and shivering.


• Cough: A dry cough is common, which may progress to a productive cough with phlegm or blood in severe cases.


• Shortness of Breath: Difficulty in breathing or shortness of breath may occur due to the infection affecting the lungs.


• Chest Pain: Some individuals may experience chest pain, which can be sharp and worsen with deep breathing or coughing.


• Muscle Aches: Generalized muscle aches and fatigue are often present, similar to flu-like symptoms.


• Headache: Headaches, sometimes severe, can occur as a result of the infection.


• Gastrointestinal Symptoms: Nausea, vomiting, and diarrhea may be present, although these symptoms are less common.

Progression of symptoms:

If left untreated, Legionnaires' disease can progress rapidly and lead to severe complications. As the infection spreads, the symptoms may worsen and additional signs may develop:

• Confusion: Mental confusion, disorientation, and changes in behavior can occur, particularly in older individuals.


• Respiratory Failure: In severe cases, the infection can cause respiratory failure, leading to a need for mechanical ventilation to assist with breathing.


• Organ Failure: Legionnaires' disease can affect other organs, such as the kidneys or liver, leading to organ failure.


• Sepsis: In some instances, the infection can cause sepsis, a life-threatening condition characterized by a systemic inflammatory response.

Seeking medical attention:

If you experience any of the symptoms associated with Legionnaires' disease, especially if you have recently been exposed to potential sources of Legionella bacteria, it is crucial to seek immediate medical attention. Early diagnosis and treatment with appropriate antibiotics can significantly improve outcomes and reduce the risk of complications.